The present invention relates to a vehicle control system. It finds particular application in conjunction with an anti-tailgating vehicle control system and will be described with particular reference thereto. It will be appreciated, however, that the invention is also amenable to other applications.
Adaptive control with braking (ACB) cruise control systems are used in vehicles for maintaining a safe relative distance between a host vehicle and forward vehicle. A torque of the host vehicle is adjusted by an ACB electronic control unit (ECU), based on a relative speed and/or relative acceleration of the host and forward vehicles, to adjust a speed of the host vehicle for maintaining the safe relative distance. ACB systems, like all cruise control systems, are active when the driver turns on the appropriate switch(es). Furthermore, like all cruise control systems, ACB systems allow the driver to apply the throttle over and above the amount of throttle being used for the cruise control function.
Collision mitigation (CM) systems operate to avoid or lessen the severity of an impact between a host and a forward vehicle using various combinations of transmission, vehicle retarder, and foundation brake controls. CM systems operate independently from the state of the ACB and/or cruise control switch(es). Also CM systems operate when the driver is applying the throttle above the amount of throttle requested by the ACB and/or cruise control system. CM systems may calculate that a collision is likely using a combination of relative speed, acceleration, and/or distance. For example if the host vehicle approaches a forward vehicle at a high relative speed and close distance, a collision may be likely and the CMS system may react.
A vehicle equipped with ACB and a typical CM system may still slowly creep up on the forward vehicle until the traveling distance is not considered safe. For example, a small relative speed may cause the ECU to determine that the time to a collision with the forward vehicle is almost infinite, even if the distance between the host and forward vehicles is short enough that the host vehicle is considered to be tailgating the forward vehicle. The CM system may not react since the relative velocity is small. The ACB system may not react if it is switched off or if the driver is manually applying the throttle.
The present invention provides a new and improved anti-tailgating system and method.